10 to 12 months:
Begins to point to some body parts following a command.
Follows simple, one part commands (i.e. Get your shoe.)
Gives objects to others upon verbal request.
Jargons with different sound combinations.
May begin to use first words.

12 to 18 months:
Can identify many objects and pictures following a verbal command.
Follows commands easily.
Listens more to the meaning of conversations.
Uses several single words.
Communicates with a combination of words and gestures.

18 to 24 months:
Understands concepts (adjectives, pronouns, plurals).
Follows compound and complex commands.
Uses two to three word combinations.
Tries to tell about experiences.
Begins to use more speech sounds such as fricatives (f, s, sh).

2 to 3 years:
Shows interest in explanations for “why” and “how” questions.
Uses phrases and short sentences for communication.
Begins to use more complex morphological and syntactical forms.

3 to 4 years:
Uses long and structurally complex sentences.
Tells stories and relates experiences from the past.
Errors in syntax include regularization of irregular forms.Speech is understandable to all listeners, although minor articulation errors are noted.